• 한국의류학회지
• /
• 제29권7호
• /
• pp.1018-1026
• /
• 2005

Recent development of 3D scanner and software is regarded as a promising method of acquiring replicas from human body indirectly. It would be very helpful if we could predict the characteristics of 2D pattern from the simple parameters related to 3D shape for ordinary user. Therefore, in this study, investigation of 2D pattern of waist/abdominal area from the 3D geometrical model was conducted for the pattern development of waist nipper. To create body models and develop the surface of them, one ortho commonly used CAD/CAM program, IDEAS(UGS-plm solutions, USA) was used. As for the size of the models, the width, thickness, and circumference ranges of adult women's torso reported in National Anthropometric Survey of Korea (1997) were used as a standard model. Seven size variations were made by changing the width of the waist only, from 19 cm to 40 cm. Therefore, simulated body models include not only the normal body but also obese body who has wider waist and abdomen width than hip width. As results, it was found that the curvature of the unfolded 2D pattern around the abdominal area decreases as the waist width increases. As the width of the waist increases more and more, so that the comparative ratios around the torso becomes in abnormal ranges, there appears inflection points and the direction of curvature was changed. 2D Patterns obtained in this research were quantified by curvature, length of the curve and angle of deflection in the reference frame box for the convenience of the actual pattern making process. It was also possible to find that the shape of patterns of abnormal body resulted in a quite interesting change in the curves of 2D pattern, which could be applied to the custom made waist nipper for obese women.

• Restorative Dentistry and Endodontics
• /
• 제47권2호
• /
• pp.16.1-16.9
• /
• 2022

Objectives: This study compared the cyclic fatigue resistance of One Curve (C wire) and F6 Skytaper (conventional austenite nickel-titanium [NiTi]), and 2 instruments with thermos-mechanically treated NiTi: Protaper Next X2 (M wire) and Hyflex CM (CM wire). Materials and Methods: Ten new instruments of each group (size: 0.25 mm, 6% taper in the 3 mm tip region) were tested using a rotary bending machine with a 60° curvature angle and a 5 mm curvature radius, at room temperature. The number of cycles until fracture was recorded. The length of the fractured instruments was measured. The fracture surface of each fragment was examined with a scanning electron microscope (SEM). The data were analyzed using one-way analysis of variance and the post hoc Tukey test. The significance level was set at 0.05. Results: At 60°, One Curve, F6 Skytaper and Hyflex CM had significantly longer fatigue lives than Protaper Next X2 (p < 0.05). No statistically significant differences were found in the cyclic fatigue lives of One Curve, F6 Skytaper, and Hyflex CM (p > 0.05). SEM images of the fracture surfaces of the different instruments showed typical features of fatigue failure. Conclusions: Within the conditions of this study, at 60° and with a 5 mm curvature radius, the cyclic fatigue life of One Curve was not significantly different from those of F6 Skytaper and Hyflex CM. The cyclic fatigue lives of these 3 instruments were statistically significantly longer than that of Protaper Next.

• 대한통합의학회지
• /
• 제7권2호
• /
• pp.189-195
• /
• 2019

Purpose : The purpose of this study was to investigate the effects of chin tuck exercise (CTE) on the craniovertebral angle (CVA), strength and endurance of deep cervical flexor (DCF) muscles in subjects with forward head posture(FHP). This study was performed on 30 subjects with FHP. Method : Thirty subjects were divided into two groups; modified CTE (n=15), conventional CTE (n=15). Both of the group performed the exercise 4 times a week for 6 weeks. The subjects performed CTE in two different methods; modified CTE, with device designed that help keep cervical lordois curve, and coventional CTE, without using device. The CVA was measured using Image software version. A pressure biofeedback unit was used to measure the strength and endurance of the DCF muscles. The data was analyzed by the paired t-test for comparing before and after changes of variables in each group and the independent t-test for comparing the between groups. Result : There was statistically significant difference of before and after strength and endurance of DCF muscles in modified CTE (p<0.05). There was statistically significant difference of before and after only endurance of DCF muscles in conventional CTE (p<0.05). There was statistically significant difference of between the two group in strength of DCF muscles (p<0.05). Conclusion : Muscle strength to stabilize the spine plays an important role in maintaining a good posture. Therefore, we suggest that the application of CTE with a device designed to maintain the lordotic curvature in the neck is likely to yield better outcomes in FHP subjects in future studies.

• 한방재활의학과학회지
• /
• 제27권1호
• /
• pp.37-51
• /
• 2017

Objectives This study was designed to identify the effect of acupuncture combined with wooden neck pillow self-exercise program (WSP). Methods 25 eligible subjects with chronic neck pain were recruited from September 2015 to August 2016. Subjects were treated by acupuncture twice a week for 4 weeks, also were educated WSP and exercised every day for 4 weeks. They were assessed using PI-NRS, NDI and the maximum muscle strength of deep cervical flexor muscles (DCF) before and after treatment. Also the Cobb's angle (C1-C7), Ishihara index, Park method were assessed for evaluating the radiographical changes. Variables were compared using paired t-test. And correlates analysis was used for analyzing relationship between differentials in the maximum muscle strength of DCF and differentials in cervical spine curvature measurement methods. Results Among the 25 subjects, 4 subjects were lost to follow-up or excluded in accordance with the criteria. Significant differences on NRS, NDI and the maximum muscle strength of DCF were seen after treatment (p<0.001). In radiological finding, cervical spine curvature measurement methods were significantly increased (p<0.001, p<0.05, p<0.05). Differentials in the maximum muscle strength of DCF significantly correlates to differentials in Ishihara index (R=0.479, p<0.05). Conclusions Acupuncture combined with WSP may decrease neck pain intensity and associated disability, and also increase the muscle strength of DCF and cervical lordosis, in patients with chronic neck pain. Especially, Improving the muscle strength of DCF has a relationship with improving Ishihara index. However, due to the design of this study, this treatment can not be compared with other treatments. Future randomized project should be needed.

• Structural Engineering and Mechanics
• /
• 제49권6호
• /
• pp.705-726
• /
• 2014

In general, cylindrically curved plates are used in ships and offshore structures such as wind towers, spa structures, fore and aft side shell plating, and bilge circle parts in merchant vessels. In a number of studies, it has been shown that curvature increases the buckling strength of a plate under compressive loading, and the ultimate load-carrying capacity is also expected to increase. In the present paper, a series of elastic and elastoplastic large deflection analyses were performed using the commercial finite element analysis program (MSC.NASTRAN/PATRAN) in order to clarify and examine the fundamental buckling and collapse behaviors of curved plates subjected to combined axial compression and lateral pressure. On the basis of the numerical results, the effects of curvature, the magnitude of the initial deflection, the slenderness ratio, and the aspect ratio on the characteristics of the buckling and collapse behavior of the curved plates are discussed. On the basis of the calculated results, the design formula was developed to predict the buckling and ultimate strengths of curved plates subjected to combined loads in an analytical manner. The buckling strength behaviors were simulated by performing elastic large deflection analyses. The newly developed formulations were applied in order to perform verification analyses for the curved plates by comparing the numerical results, and then, the usefulness of the proposed method was demonstrated.

• 한국강구조학회 논문집
• /
• 제21권4호
• /
• pp.351-360
• /
• 2009

본 연구에서는 스테인리스 강관의 구조재로서 적용성 검토를 위해 편심 축하중을 받는 스테인리스 원형강관 보-기둥에 대한 좌굴강 도와 거동을 파악하고자 한다. 주요변수는 축력과 양단 비대칭 모멘트를 받는 이중곡률 보-기둥에 세장비(細長比)와 편심비(e/k)로 한 스테인리 스 원형강관의 최대내력 및 변형능력 등의 역학적 특성을 규명하며, 이론해석을 통한 실험값과 비교함으로서 스테인리스 강관 구조설계을 위한 기초 자료를 구하는데 그 목적이 있다. 실험결과를 해석결과와 비교해본 결과, 세장비 70의 편심비가 0인 시험체만이 낮고, 그 외 모든 시험체는 해석을 통한 M-P 상관곡선을 상회하는 결과를 보이나, 편심비가 작을수록 해석값에 근접하고 있어, 이론해석에서 적용한 세장비를 고려한 좌굴계수나 강도저감계수가 스테인리스 원형강관에 대해서는 별도의 값이 적용될 가능성이 있는 것으로 판단되며, 더 많은 실험에 의해 확증되어야 할 것이다.

• Journal of Welding and Joining
• /
• 제27권2호
• /
• pp.32-37
• /
• 2009

In shipyard, plate forming is widely used to form the ship hull plate in various shapes. Line heating method by using a flame torch is one of the major shipbuilding processes carried out by skilled workers. Since the forming characteristics depend upon their experiences in manual forming, there are much variations between products and difficulties in communication between engineers and workers. Hence, it needs to develop an automatic forming system which can not only reduce the working time and rework costs but also improve the working environment and hull forming productivity. One of the final goals of plate forming automation is to form a target shape from the initial plate automatically. For automated plate forming, it is required to determine where and how to heat on the plate. To realize this procedure, the inverse problem should be first solved and the effect of curvature shape formed at the heating path should be investigated. In this study, the inverse problem was solved by geometrical approach using the relationship between bending angle and radius of curvature of the curved shape. In addition, experiments of two-dimensional plate forming were performed with the distance-based method considering the curved bending with curvature. The result of the formed shape agreed considerably well with the target shape.

• 비파괴검사학회지
• /
• 제24권4호
• /
• pp.307-314
• /
• 2004

배관의 축방향 균열 검사를 위하여 원주 방향으로 진행하는 유도초음파 모드를 적용하였다. 배관의 곡률을 변수로 원주 유도초음파의 분산선도를 계산하였으며 이를 배관 검사에 적용하기 위하여 중수로 피더관의 곡관부 축방향 균열을 탐지에 적용하였다. 상대적으로 낮은 주파수에서는 Lamb 파 특성을 따르나 주파수가 증가함에 따라 평판의 경우, 즉 곡률이 무한대인 경우 첫 번째 $A_0$ 모드와 두 번째 $S_0$ 모드가 합쳐져서 Rayleigh 모드 형태로 변화한다. 한편 곡률을 가진 배관의 경우는 주파수가 증가하더라도 첫 번째 모드와 두 번째 모드가 합쳐지지 않았다. 이러한 해석을 기초로 하여 배관의 일종인 중수로 피더관 곡관부 축방향 결함을 탐지하기 위하여 사각 탐촉자를 사용하여 Rocking 원주 유도초음파 기법을 적용하였다. 원주 방향으로 유도파를 진행시키면서 인공 결함으로부터의 수집된 신호를 분석하여 진동 모드를 확인하였으며 두께 대비 10% 깊이의 notch도 검출할 수 있음을 확인할 수 있었다.

• 한방재활의학과학회지
• /
• 제33권4호
• /
• pp.185-193
• /
• 2023

Objectives This study was conducted to find out the correlation between lumbar malposition and lumbar disc herniation. Methods Among the patients who visited Gwangju Jaseng Hospital of Korean Medicine from January 2019 to January 2021, taking 92 patients under age 60 who had the records of X-rays and magnetic resonance imaging (MRI) images as the research subjects, Cobb's angle was measured in anterior-posterior (AP) view and lateral (LAT) view, the number of displacements was scored by listing categories defined by The Korean Society of Chuna Manual Medicine for Spine and Nerves. The degree of lumbar intervertebral disc herniation was expressed as a percentage according to the method of Kato, etc., and the correlation between each factor was analyzed. Results AP curvature and MRI herniation index showed significant positive correlation in L4-L5 level but there was no significant difference in L5-S1 level. LAT curvature and MRI herniation index had no correlation in L4-L5 level, but there was a significant negative correlation in L5-S1 level. Malposition score and MRI herniation index had a significant positive correlation in L5-S1 level, whereas there was no correlation in L4-L5. Conclusions As a result of the study, AP curvature and MRI herniation index showed a significant positive tendency in L4-L5 lumbar spine, and LAT curvature and MRI herniation index showed a significant negative tendency in L5-S1 lumbar spine. Malposition score and MRI herniation index were found to have a significant positive tendency in L5-S1 lumbar spine.

• 한국농공학회지
• /
• 제34권1호
• /
• pp.78-86
• /
• 1992

This paper aims at investigating the effect of steel ratio and the magnitude of edge-ratio on the mechanical characteristics of reinforced concrete ring sector plate. The influence of steel bars was taken into account by coupling stiffness matrix of the steel bar element with that of the concrete plate element without dealing with separate element of steel bar and by establishing the composite stiffness matrix, which leads to the desirable result which does not increase th number of element could be obtained. Through case studies with 6 cases various steel ratios in ring sector plate supported at four edges and 4 cases with different open angles, the influence of the steel ratio was examined. A numerical analysis to find out the effect of the steel ratio d ue to above mentioned cases was carried out by 4 boundary conditions ; all edges clamped (B.C-1), all edges simply supported (B.C-2), curvilinear two edges clamped and other edges free (B.C-3) and curvilinear two edges simply supported and other edges free(B.C-4). The main results obtained are summarized as follows : 1. The effect of steel ratio on the magnitude of lateral deflection and x-directional bending moment at the center of sector plate and the midpoint of outer and inner curvilinear edges is almost the same up to $30^{\circ}$ of open angle. Beyond $30^{\circ}$ of the angle, the larger the angle, the greater the effect of ratio. 2. In design works using balanced steel ratio, the effect of steel bar can be ignored. But for larger open angles, especially greater than $90^{\circ}$, it proves desirable to consider the effect of steel bar. 3. The effect of the arc length of center circle/straight edge on lateral deflection and bending moment is remarkable in B.C-2. For larger open angle, the effect is also noted except for B.C-3 which turn out hardly affected. 4. The effect of the radius of curvature/straight side length on lateral deflection and x-directional bending moment is noted in B.C-2. As open angle increases, B.C-1 and B.C-3 almost agree and B.C-2 approaches B.C-4.